Exhaust manifold - structural element of the exhaust system, designed for removal of exhaust gases from the individual cylinders in a common pipe. Another function of the exhaust manifold is to provide effective purging and filling of the combustion chambers.
The exhaust manifold is rigidly fixed to the cylinder head. At the exit it is joined by the catalytic converter or exhaust pipe. Between the exhaust manifold and the cylinder head gasket is placed, which prevents leakage of exhaust gas in the engine compartment. Exhaust manifold working in very difficult conditions, characterized by high temperatures (1300 ° C) and pressure.
There are two types of exhaust manifolds - solid and tubular. The one-piece collector has short channels, which are combined in a common cell. Made of heat-resistant cast iron. The one-piece exhaust manifold has a low efficiency of removal of exhaust gases and the purging of the combustion chamber, as short channels constitute an obstacle in the form of pulses of gas of each cylinder. On the other hand integral exhaust manifold is simple to manufacture and has a low cost.
On modern cars are installed mainly tubular exhaust manifolds, which are effective at medium and high speed, improve the power characteristics of the engine. Tubular exhaust manifolds are made of stainless steel, ceramics less. To achieve the best parameters of exhaust system and purging combustion chamber length, pipe diameter and the design (form) must be optimized.
The movement of the exhaust gas in the exhaust system is an oscillatory process. Short pipe exhaust manifold allows to achieve a resonance effect in which there is the best blowing combustion chambers at high engine speeds. With a long pipe on the contrary, the resonance effect is achieved at low rpm. The length of the pipe to prevent the return exhaust gas to neighboring combustion chamber, which is not yet closed discharge valves.
Small diameter pipes provides high speed exhaust gas, at which the best inertial purge of the combustion chamber and the rated torque at low and medium engine speeds. On the other hand small diameter pipe create additional resistance to flow at high engine speeds. With large diameter pipes get power increase at high rpm and the reduction in the lowest.
Currently, two common schemes tubular exhaust manifolds:
1) or short collector 4-1 (four tubes are connected to one tube);
2) long or collector 4-2-1 (four tubes are connected in pairs and further connected to one tube).
Tubular exhaust manifold is an important element of the car tuning. To one machine it may be presented with several designs and exhaust manifolds, respectively, achieve different effects. Short manifold provides extra power in a narrow rpm range. Long manifold more versatile, as it provides an increase in power and torque over a wide engine speed range.
🔎 exhaust manifold SkyActiv-G
For example, exhaust manifold 4-2-1 scheme applied to gasoline engines, which are installed on cars #Mazda technology SkyActiv-G. In addition to the growth of the power in these engines implemented a higher compression ratio, and by improving the ventilation of the cylinder detonation in the cylinders does not occur.
During operation of the engine exhaust manifold heats the air in the engine compartment, respectively, heated air into the intake system and reduced power. To counteract this phenomenon made intake manifold insulation. There are different ways of thermal insulation: heat-reflecting panel installation, the device high temperature braid tube made reservoir with double walls.
The exhaust manifold is rigidly fixed to the cylinder head. At the exit it is joined by the catalytic converter or exhaust pipe. Between the exhaust manifold and the cylinder head gasket is placed, which prevents leakage of exhaust gas in the engine compartment. Exhaust manifold working in very difficult conditions, characterized by high temperatures (1300 ° C) and pressure.
There are two types of exhaust manifolds - solid and tubular. The one-piece collector has short channels, which are combined in a common cell. Made of heat-resistant cast iron. The one-piece exhaust manifold has a low efficiency of removal of exhaust gases and the purging of the combustion chamber, as short channels constitute an obstacle in the form of pulses of gas of each cylinder. On the other hand integral exhaust manifold is simple to manufacture and has a low cost.
On modern cars are installed mainly tubular exhaust manifolds, which are effective at medium and high speed, improve the power characteristics of the engine. Tubular exhaust manifolds are made of stainless steel, ceramics less. To achieve the best parameters of exhaust system and purging combustion chamber length, pipe diameter and the design (form) must be optimized.
The movement of the exhaust gas in the exhaust system is an oscillatory process. Short pipe exhaust manifold allows to achieve a resonance effect in which there is the best blowing combustion chambers at high engine speeds. With a long pipe on the contrary, the resonance effect is achieved at low rpm. The length of the pipe to prevent the return exhaust gas to neighboring combustion chamber, which is not yet closed discharge valves.
Small diameter pipes provides high speed exhaust gas, at which the best inertial purge of the combustion chamber and the rated torque at low and medium engine speeds. On the other hand small diameter pipe create additional resistance to flow at high engine speeds. With large diameter pipes get power increase at high rpm and the reduction in the lowest.
Currently, two common schemes tubular exhaust manifolds:
1) or short collector 4-1 (four tubes are connected to one tube);
2) long or collector 4-2-1 (four tubes are connected in pairs and further connected to one tube).
Tubular exhaust manifold is an important element of the car tuning. To one machine it may be presented with several designs and exhaust manifolds, respectively, achieve different effects. Short manifold provides extra power in a narrow rpm range. Long manifold more versatile, as it provides an increase in power and torque over a wide engine speed range.
🔎 exhaust manifold SkyActiv-G
For example, exhaust manifold 4-2-1 scheme applied to gasoline engines, which are installed on cars #Mazda technology SkyActiv-G. In addition to the growth of the power in these engines implemented a higher compression ratio, and by improving the ventilation of the cylinder detonation in the cylinders does not occur.
During operation of the engine exhaust manifold heats the air in the engine compartment, respectively, heated air into the intake system and reduced power. To counteract this phenomenon made intake manifold insulation. There are different ways of thermal insulation: heat-reflecting panel installation, the device high temperature braid tube made reservoir with double walls.
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